

import java.util.Scanner;

public class Study {

	public static void main(String[] args) {
		//鍒涘缓鎵弿鍣�
		Scanner sr= new Scanner(System.in);
		// 瑕佹眰鐢ㄦ埛杈撳叆鍗婂緞鐨勫�硷紝鎵撳嵃鍑轰互姝ゅ�间负鍗婂緞鐨勫渾鐨勯潰绉�
		System.out.println("璇疯緭鍏ュ崐寰勶細锛堝崟浣嶇背锛�");
		double jing = sr.nextDouble();
		final double PI=3.14;
		//2. 姹傚渾鐨勯潰绉殑鍏紡锛毾�r虏銆�
		
		System.out.println("鍦嗙殑闈㈢Н鏄細"+PI*jing*jing+"骞虫柟绫�");
		//3. 蟺鍙�3.14銆�
		//4. r鐢辩敤鎴疯緭鍏ュ苟瀛樺叆涓�涓彉閲忎腑锛屾鍙橀噺鐢╠ouble姣旇緝鍚堥�傦紝鍥犱负鐢ㄦ埛鍙兘浼氳緭鍏ュ皬鏁般��  


	}

}
